Add protections around exporting unknown recipients in dlists.

app/src/main/java/org/thoughtcrime/securesms/backup/v2/database/DistributionListTablesArchiveExtensions.kt

@@ -7,19 +7,20 @@ package org.thoughtcrime.securesms.backup.v2.database
 
 import org.signal.core.util.select
 import org.signal.core.util.withinTransaction
+import org.thoughtcrime.securesms.backup.v2.ExportState
 import org.thoughtcrime.securesms.backup.v2.exporters.DistributionListArchiveExporter
 import org.thoughtcrime.securesms.database.DistributionListTables
 import org.thoughtcrime.securesms.database.model.DistributionListId
 import org.thoughtcrime.securesms.database.model.DistributionListPrivacyMode
 import org.thoughtcrime.securesms.recipients.RecipientId
 
-fun DistributionListTables.getAllForBackup(selfRecipientId: RecipientId): DistributionListArchiveExporter {
+fun DistributionListTables.getAllForBackup(selfRecipientId: RecipientId, exportState: ExportState): DistributionListArchiveExporter {
   val cursor = readableDatabase
     .select()
     .from(DistributionListTables.ListTable.TABLE_NAME)
     .run()
 
-  return DistributionListArchiveExporter(cursor, this, selfRecipientId)
+  return DistributionListArchiveExporter(cursor, this, selfRecipientId, exportState)
 }
 
 fun DistributionListTables.getMembersForBackup(id: DistributionListId): List<RecipientId> {

app/src/main/java/org/thoughtcrime/securesms/backup/v2/exporters/ChatItemArchiveExporter.kt

@@ -317,6 +317,11 @@ class ChatItemArchiveExporter(
         }
 
         MessageTypes.isGroupV2(record.type) && MessageTypes.isGroupUpdate(record.type) -> {
+          if (builder.authorId != selfRecipientId.toLong() && exportState.recipientIdToAci[builder.authorId] == null) {
+            Log.w(TAG, ExportSkips.groupUpdateHasInvalidAuthor(record.dateSent))
+            continue
+          }
+
           val update = record.toRemoteGroupUpdate() ?: continue
           if (update.groupChange!!.updates.isEmpty()) {
             Log.w(TAG, ExportSkips.groupUpdateHasNoUpdates(record.dateSent))
@@ -430,7 +435,7 @@ class ChatItemArchiveExporter(
 
       if (record.latestRevisionId == null) {
         builder.revisions = revisionMap.remove(record.id)?.repairRevisions(builder) ?: emptyList()
-        val chatItem = builder.build().validateChatItem(exportState) ?: continue
+        val chatItem = builder.build().validateChatItem(exportState, selfRecipientId) ?: continue
         buffer += chatItem
       } else {
         var previousEdits = revisionMap[record.latestRevisionId]
@@ -1340,6 +1345,10 @@ private fun ByteArray.toRemoteBodyRanges(dateSent: Long): List<BackupBodyRange>
       null
     }
 
+    if (mention == null && style == null) {
+      return emptyList()
+    }
+
     BackupBodyRange(
       start = it.start,
       length = it.length,
@@ -1589,7 +1598,7 @@ private fun <T> ExecutorService.submitTyped(callable: Callable<T>): Future<T> {
   return this.submit(callable)
 }
 
-private fun ChatItem.validateChatItem(exportState: ExportState): ChatItem? {
+private fun ChatItem.validateChatItem(exportState: ExportState, selfRecipientId: RecipientId): ChatItem? {
   if (this.standardMessage == null &&
     this.contactMessage == null &&
     this.stickerMessage == null &&
@@ -1610,6 +1619,16 @@ private fun ChatItem.validateChatItem(exportState: ExportState): ChatItem? {
     return null
   }
 
+  if (this.updateMessage != null && this.updateMessage.canOnlyBeAuthoredBySelf() && this.authorId != selfRecipientId.toLong()) {
+    Log.w(TAG, ExportSkips.individualChatUpdateNotAuthoredBySelf(this.dateSent))
+    return null
+  }
+
+  if (this.incoming != null && exportState.recipientIdToAci[this.authorId] == null && exportState.recipientIdToE164[this.authorId] == null) {
+    Log.w(TAG, ExportSkips.incomingMessageAuthorDoesNotHaveAciOrE164(this.dateSent))
+    return null
+  }
+
   return this
 }
 
@@ -1621,6 +1640,13 @@ private fun ChatUpdateMessage.isOnlyForIndividualChats(): Boolean {
     this.simpleUpdate?.type == SimpleChatUpdate.Type.PAYMENTS_ACTIVATED
 }
 
+private fun ChatUpdateMessage.canOnlyBeAuthoredBySelf(): Boolean {
+  return this.simpleUpdate?.type == SimpleChatUpdate.Type.REPORTED_SPAM ||
+    this.simpleUpdate?.type == SimpleChatUpdate.Type.MESSAGE_REQUEST_ACCEPTED ||
+    this.simpleUpdate?.type == SimpleChatUpdate.Type.BLOCKED ||
+    this.simpleUpdate?.type == SimpleChatUpdate.Type.UNBLOCKED
+}
+
 private fun List<ChatItem>.repairRevisions(current: ChatItem.Builder): List<ChatItem> {
   return if (current.standardMessage != null) {
     val filtered = this

app/src/main/java/org/thoughtcrime/securesms/backup/v2/exporters/DistributionListArchiveExporter.kt

@@ -14,6 +14,7 @@ import org.signal.core.util.requireNonNullString
 import org.signal.core.util.requireObject
 import org.thoughtcrime.securesms.backup.v2.ArchiveRecipient
 import org.thoughtcrime.securesms.backup.v2.ExportOddities
+import org.thoughtcrime.securesms.backup.v2.ExportState
 import org.thoughtcrime.securesms.backup.v2.database.getMembersForBackup
 import org.thoughtcrime.securesms.backup.v2.proto.DistributionList
 import org.thoughtcrime.securesms.backup.v2.proto.DistributionListItem
@@ -32,7 +33,8 @@ private val TAG = Log.tag(DistributionListArchiveExporter::class)
 class DistributionListArchiveExporter(
   private val cursor: Cursor,
   private val distributionListTables: DistributionListTables,
-  private val selfRecipientId: RecipientId
+  private val selfRecipientId: RecipientId,
+  private val exportState: ExportState
 ) : Iterator<ArchiveRecipient>, Closeable {
 
   override fun hasNext(): Boolean {
@@ -66,7 +68,7 @@ class DistributionListArchiveExporter(
         deletionTimestamp = record.deletedAtTimestamp
       )
     } else {
-      val members = record.members.toRemoteMemberList(selfRecipientId)
+      val members = record.members.toRemoteMemberList(selfRecipientId, exportState)
       DistributionListItem(
         distributionId = record.distributionId.asUuid().toByteArray().toByteString(),
         distributionList = DistributionList(
@@ -104,10 +106,11 @@ private fun DistributionListPrivacyMode.toBackupPrivacyMode(memberCount: Int): D
   }
 }
 
-private fun List<RecipientId>.toRemoteMemberList(selfRecipientId: RecipientId): List<Long> {
+private fun List<RecipientId>.toRemoteMemberList(selfRecipientId: RecipientId, exportState: ExportState): List<Long> {
   val filtered = this.filter { it != selfRecipientId }.map { it.toLong() }
   if (filtered.size != this.size) {
     Log.w(TAG, ExportOddities.distributionListHadSelfAsMember())
   }
-  return filtered
+
+  return filtered.filter { exportState.recipientIdToAci[it] != null || exportState.recipientIdToE164[it] != null }
 }

app/src/main/java/org/thoughtcrime/securesms/backup/v2/processor/RecipientArchiveProcessor.kt

@@ -82,7 +82,7 @@ object RecipientArchiveProcessor {
       }
     }
 
-    db.distributionListTables.getAllForBackup(selfRecipientId).use { reader ->
+    db.distributionListTables.getAllForBackup(selfRecipientId, exportState).use { reader ->
       for (recipient in reader) {
         exportState.recipientIds.add(recipient.id)
         emitter.emit(Frame(recipient = recipient))